Theorem sseqtrrd 3186

Description: Substitution of equality into a subclass relationship. (Contributed by NM, 25-Apr-2004.)

Hypotheses

Ref	Expression
sseqtrrd.1	|- ( ph -> A C_ B )
sseqtrrd.2	|- ( ph -> C = B )

Assertion

Ref	Expression
sseqtrrd	|- ( ph -> A C_ C )

Proof of Theorem sseqtrrd

Step	Hyp	Ref	Expression
1		sseqtrrd.1	. 2 |- ( ph -> A C_ B )
2		sseqtrrd.2	. . 3 |- ( ph -> C = B )
3	2	eqcomd 2176	. 2 |- ( ph -> B = C )
4	1, 3	sseqtrd 3185	1 |- ( ph -> A C_ C )

Syntax hints:   -> wi 4   = wceq 1348   C_ wss 3121

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-5 1440  ax-7 1441  ax-gen 1442  ax-ie1 1486  ax-ie2 1487  ax-8 1497  ax-11 1499  ax-4 1503  ax-17 1519  ax-i9 1523  ax-ial 1527  ax-i5r 1528  ax-ext 2152

This theorem depends on definitions:  df-bi 116  df-nf 1454  df-sb 1756  df-clab 2157  df-cleq 2163  df-clel 2166  df-in 3127  df-ss 3134

This theorem is referenced by:  sseqtrrid  3198  fnfvima  5727  tfrlemiubacc  6306  tfr1onlemubacc  6322  tfrcllemubacc  6335  rdgivallem  6357  nnnninf  7098  dfphi2  12161  ctinf  12372  toponss  12777  ssntr  12875  iscnp3  12956  cnprcl2k  12959  tgcn  12961  tgcnp  12962  ssidcn  12963  cncnp  12983  txcnp  13024  imasnopn  13052  hmeontr  13066  blssec  13191  blssopn  13238  xmettx  13263  metcnp  13265  nnsf  13998  nninfsellemsuc  14005